Research Article: Pedigree analysis of Czech Holstein calves with schistosoma reflexum

Date Published: April 2, 2012

Publisher: BioMed Central

Author(s): Jindrich Citek.

http://doi.org/10.1186/1751-0147-54-22

Abstract

Schistosoma reflexum (SR) is congenital syndrome briefly characterized by visceral eventration, severe dorsoflexion and ankylosis of the spine and arthrogryposis. A genetic etiology has been proposed, but conclusive evidence has not yet been provided.

Pedigree analysis was carried out in 29 cases of SR in Czech Holsteins and Holstein crosses. Genetic relationship was evaluated and inbreeding coefficients calculated. Pedigrees of 15 Czech Holsteins fathering non-SR affected calves were used for comparison.

Twenty-one cases occurred in one pedigree founded by three sires while three SR calves occurred in another pedigree with a common grandfather. The sex ratio between affected males and females was 11:6. Affected calves shared common ancestors different from those shared by the unaffected calves. The inbreeding coefficient in the SR affected calves was not increased compared to unaffected calves.

The findings are consistent with SR being inherited autosomal recessively. Further studies are however needed to confirm this and therefore a breeding trial is recommended where a suspected heterozygous sire is mated to closely related females.

Partial Text

Schistosoma reflexum (SR) is congenital syndrome briefly characterized by severe abdominal fissure with total eventration of viscera, marked dorsoflexion, and ankylosis of the spine and limbs. It occurs in all food animals, but is most common in cattle. SR usually requires assisted delivery, in most cases Caesarean section or foetotomy [1,2]. Although SR is rare, the high risk of dystocia in such cases is a welfare problem and the required veterinary assistance has a negative economic impact on farm economy.

Twenty-nine cases of SR diagnosed and reported by veterinary surgeons to the Czech surveillance program for bovine genetic disorders were included. The study was limited to Holstein and Holstein-crossbred calves fathered by sires born between January 1986 and December 2001. The sires were born in the Czech Republic or included in the herd book due to semen import. Parentage control was not performed to confirm registered descent. The cases occurred on farms spread across the Czech Republic. Six cases were females, 11 were males while the sex was not recorded in 12 cases.

Although the diagnosis of SR was based on field observations by a number of veterinary surgeons, the diagnoses are considered reliable as the morphology of SR is probably well known to veterinarians. Detailed morphological descriptions were not available, although additional defects as e.g. fissure of the genitals and polypodia were reported.

Analysis of pedigree data showed that 24 out of 29 registered SR cases occurred in two breeding lines (Figures 1 and 2). Within the large pedigree (Figure 1), some animals as e.g. sire XII/15, were genetically closely related to several SR cases. It should be clearly emphasized, that in a large complicated pedigree such as that in Figure 1, the common ancestors may occur by chance, especially if they have been widely used. This is the case for I/1 (Osborndale Ivanhoe, born 1952, US1189870), I/2 (Round Oak Rag Apple Elevation, born 1965, US1491007), II/1 (Pawnee Farm Arlinda Chief, born 1962, US1427381) and III/2 (S-W-D Valiant, born 1973, US1650414) that are important breeding sires used worldwide in Holstein cattle breeding. Sires as these will by chance occur the pedigree of defective Holstein calves [7]. However, the occurrence of sires such as XII/15 (Figure 1) and V/2 (Figure 2) related to several cases of SR may indicate a genetic aetiology.

The findings are consistent with SR being inherited autosomal recessively. Further studies are however needed to confirm this and therefore a breeding trial is recommended where a suspected heterozygous sire is mated to closely related females.

The author declares that they have no competing interests.

JC made the design of the study. He found the common ancestors, made the common pedigrees, evaluated the control pedigrees, inbreeding coefficients, wrote the manuscript, and formulated conclusions. The author read and approved the final manuscript.

 

Source:

http://doi.org/10.1186/1751-0147-54-22

 

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